1. Field of the Invention
The invention relates to a method and an antenna system, more particularly to a method and an antenna system capable of automatically setting optimum antenna units as working antenna units.
2. Description of the Related Art
Multiple-input and multiple output (MIMO) is a common wireless communication technology which is nowadays widely applied to various kinds of communication systems, such as the third-generation of mobile telecommunications (3G) and the fourth-generation of mobile telecommunications (4G). A wireless router is an ordinary example of the application of MIMO technology.
Referring to FIG. 1, a schematic diagram which illustrates an antenna system 9 adopting MIMO technology is provided. The antenna system 9 includes a control circuit 91, a plurality of radio frequency (RF) modules 92, 93 connected electrically to the control circuit 91, a plurality of antenna units 94, 95 connected electrically to the RF module 92, and a plurality of antenna units 96, 97 connected electrically to the RF module 93. The control circuit 91, by means of the RF modules 92, 93, is able to control one of the antenna units 94, 95 and one of the antenna units 96, 97 for wireless signal transmission. For example, the antenna units 94, 96 may be external antennas disposed on an electronic device (e.g., a wireless router), and the antenna units 95, 97 may be internal antennas disposed in the electronic device. When the antenna system 9 which adopts MIMO technology operates to transmit or receive wireless signals, the antenna units 94, 96 must cooperate to form a group for operation, and the antenna units 95, 97 must also cooperate to form a group for operation. However, the antenna system 9 only activates one of the groups of the antenna units at a time.
When a user operates the electronic device, a switch of the electronic device may be utilized to switch between transmission paths, which are constituted respectively by the RF module 92 and the antenna unit 94, the RF module 92 and the antenna unit 95, the RF module 93 and the antenna unit 96, and the RF module and the antenna unit 97, for wireless signal transmission. The user usually selects one of the aforementioned transmission paths according to a subjective usage experience. In other words, when the user considers the wireless transmission efficiency of one of the transmission paths being insufficient, another one of the transmission paths may be selected by the user for transmission in an attempt to promote the transmission efficiency. However, this kind of selection strategy is performed without taking into account objective information associated with network quality, and thus is relatively ineffective.
Moreover, when the antenna system 9 is in operation, since the group of the antenna units 94, 96 and the group of the antenna units 95, 97 are required to work separately, and since the antenna units 94, 95, 96, 97 may not be flexibly adjusted to form different groups for operation (for example, the antenna unit 94 may not cooperate with the antenna unit 97 to form a group for operation), flexibility of matching between the antenna units is restricted, so that performance of the antenna system 9 is adversely influenced.